app: restructure and start building p15 output

pkg/tools/asn1obj/bitstring.go

@@ -0,0 +1,27 @@
+package asn1obj
+
+import (
+	"encoding/asn1"
+	"math/bits"
+)
+
+// BitString returns a BIT STRING of the content
+func BitString(content []byte) []byte {
+	bs := asn1.BitString{
+		Bytes: content,
+	}
+
+	// drop trailing 0s by removing them from overall length
+	if len(content) > 0 {
+		trailing0s := bits.TrailingZeros8(content[len(content)-1])
+		bs.BitLength = 8*len(content) - trailing0s
+	}
+
+	// should never error
+	asn1result, err := asn1.Marshal(bs)
+	if err != nil {
+		panic(err)
+	}
+
+	return asn1result
+}

pkg/tools/asn1obj/integer.go

@@ -0,0 +1,17 @@
+package asn1obj
+
+import (
+	"encoding/asn1"
+	"math/big"
+)
+
+// Integer returns an ASN.1 OBJECT IDENTIFIER with the oidValue bytes
+func Integer(bigInt *big.Int) []byte {
+	// should never error
+	asn1result, err := asn1.Marshal(bigInt)
+	if err != nil {
+		panic(err)
+	}
+
+	return asn1result
+}

pkg/tools/asn1obj/misc.go

@@ -0,0 +1,27 @@
+package asn1obj
+
+import "encoding/asn1"
+
+// Explicit wraps another ASN.1 Object with the EXPLICIT wrapper using
+// the tag number specified
+func Explicit(explicitTagNumber int, wrappedElement []byte) []byte {
+	raw := asn1.RawValue{
+		Class:      asn1.ClassContextSpecific,
+		Tag:        explicitTagNumber,
+		IsCompound: true,
+		Bytes:      wrappedElement,
+	}
+
+	// should never error
+	asn1result, err := asn1.Marshal(raw)
+	if err != nil {
+		panic(err)
+	}
+
+	return asn1result
+}
+
+// Null returns the NULL value
+func Null() []byte {
+	return asn1.NullBytes
+}

pkg/tools/asn1obj/octetstring.go

@@ -0,0 +1,23 @@
+package asn1obj
+
+import (
+	"encoding/asn1"
+)
+
+// OctetString returns an OCTET STRING of the content
+func OctetString(content []byte) []byte {
+	raw := asn1.RawValue{
+		Class:      asn1.ClassUniversal,
+		Tag:        asn1.TagOctetString,
+		IsCompound: false,
+		Bytes:      content,
+	}
+
+	// should never error
+	asn1result, err := asn1.Marshal(raw)
+	if err != nil {
+		panic(err)
+	}
+
+	return asn1result
+}

pkg/tools/asn1obj/oid.go

@@ -0,0 +1,19 @@
+package asn1obj
+
+import "encoding/asn1"
+
+var (
+	OIDPkscs15Content     = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 15, 3, 1} // pkcs15content (PKCS #15 content type)
+	OIDrsaEncryptionPKCS1 = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1}     // rsaEncryption (PKCS #1)
+)
+
+// ObjectIdentifier returns an ASN.1 OBJECT IDENTIFIER with the oidValue bytes
+func ObjectIdentifier(oid asn1.ObjectIdentifier) []byte {
+	// should never error
+	asn1result, err := asn1.Marshal(oid)
+	if err != nil {
+		panic(err)
+	}
+
+	return asn1result
+}

pkg/tools/asn1obj/sequence.go

@@ -0,0 +1,26 @@
+package asn1obj
+
+import "encoding/asn1"
+
+// Sequence returns an ASN.1 SEQUENCE with the specified content
+func Sequence(content [][]byte) []byte {
+	val := []byte{}
+	for i := range content {
+		val = append(val, content[i]...)
+	}
+
+	raw := asn1.RawValue{
+		Class:      asn1.ClassUniversal,
+		Tag:        asn1.TagSequence,
+		IsCompound: true,
+		Bytes:      val,
+	}
+
+	// should never error
+	asn1result, err := asn1.Marshal(raw)
+	if err != nil {
+		panic(err)
+	}
+
+	return asn1result
+}

pkg/tools/asn1obj/utf8string.go

@@ -0,0 +1,16 @@
+package asn1obj
+
+import (
+	"encoding/asn1"
+)
+
+// UTF8String returns the specified string as a UTF8String
+func UTF8String(s string) []byte {
+	// should never error
+	asn1result, err := asn1.MarshalWithParams(s, "utf8")
+	if err != nil {
+		panic(err)
+	}
+
+	return asn1result
+}